1. Technical Field of the Invention
The present invention generally relates to methods and structures for testing network interface devices.
2. Description of the Related Art
Network interfaces for connecting a device, such as a computer, to a network, commonly include a media access controller (xe2x80x9cMACxe2x80x9d) and a physical layer device (xe2x80x9cPHYxe2x80x9d or xe2x80x9cPHY devicexe2x80x9d). The MAC insures that data being sent is properly formatted and dressed, so that frames or packets of data are properly recognized by other devices on the network. Signals from the MAC are sent to the PHY which handles the actual transmission of signals on a network medium. The network medium may be any of a variety of well known media, such as fiber-optic cables or various types of dedicated metal-wire cables such as twisted shielded pair, 10 BASE-T, and wiring for telephone lines. Alternatively, the network medium may include wireless communication. During the manufacture of network interface components or devices, such as the PHY and MAC devices described above, the components are tested at various stages of the process. Manufacturers have significant economic inventive to detect and discard faulty components as early in the manufacturing process as possible.
In evaluating the performance of a device it is desirable to be able to independently test the internal blocks of the device. Prior devices have utilized additional dedicated pins to facilitate such testing. However, it will be appreciated that the use of dedicated pins for testing internal components may increase product cost, size, and complexity.
Accordingly, it will be appreciated that it would be desirable to have network interface devices and methods for testing such devices which overcome the aforesaid disadvantages.
The network interface device has an external interface and multiple blocks of operative components, pairs of the blocks having internal connections between them. The network interface device is configurable to reroute one or to more of the internal connections onto the external interface to allow testing of the blocks of the device. The external interface may also be coupled so as to pass data between the network interface device and higher levels in a network protocol stack. In an exemplary embodiment a network interface device has a media access controller (MAC) and a physical layer device (PHY). An internal (media independent interface (MII) between the MAC and the PHY may be selectively rerouted to an external MII for independently testing operation of either the MAC or the PHY.
According to an aspect of the invention, a network interface device has multiple blocks with internal connections, one or more of the internal connections being selectively reroutable to an external interface of the network interface device.
According to another aspect of the invention, a method of testing internal blocks of a network interface device includes rerouting one or more internal connections of the network interface device to an external interface of the device.
According to yet another aspect of the invention, a network interface device includes a MAC, a PHY, and a switchable connection between the MAC and the PHY for re-routing all or part of the interface to an external interface of the device.
According to still another aspect of the invention, a network interface device includes an external media independent interface (Mul), the Mul being usable in normal operation to interface with devices on a higher level in a network protocol stack, and being usable to test operation of individual blocks of the device.
According to a further aspect of the invention, a network medium interface includes first and second blocks, an external interface, and a switchable connection, wherein the switchable connection may be selectively configured either to internally connect the blocks to each other, or to connect one of the blocks to a transmit portion and/or a receive portion of the external interface.
According to a still further aspect of the invention, a method of testing operation of an internal block of a network medium interface includes the steps of reconfiguring the device so that a normally-internally-connected connection of the block are connected to an external interface; inputting test signals to the block; and evaluating output of the block.
To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.